Unconventional gas is produced or extracted using techniques other than conventional oil well methods. Extracting unconventional gas is becoming more important, as conventional oil reserves are becoming more scarce.
Typically, unconventional gas is found in reservoirs which are gas bearing but very tight. These unconventional reservoirs include reservoirs such as tight sands, shale gas, shale oil, coalbed methane, tight carbonate, and gas hydrate reservoirs. In general, these reservoirs are largely impermeable. Thus, the horizontal wells in these reservoirs can be hydraulically fractured in many stages using a hydraulic fracturing technique known as multistage hydraulic fracturing in order for these reservoirs to produce gas or oil in commercial quantities. The process of hydraulic fracturing entails pumping fracturing fluid into the region. Fracturing fluid is generally composed of water mixed with proppant and/or resin coated proppant and chemicals such as gelling agents, crosslinkers, and breakers. The fracturing fluid is pumped into the reservoir at high pressures. This fracturing pressure must exceed the formation parting pressure or fracturing gradient to break down the formation and propagate a fracture. The induced hydraulic fracture will propagate further into the formation and activate natural fractures. The proppant in the fracturing fluid will fill the induced fractures, thus making those fractures conductive channels. Upon completion, the well is shut down allowing the breaker to activate and break the crosslinked gel. The well is put on production for fracture cleanup, which can take weeks. Usually, several stages of this fracturing treatment are carried out in a single well to create maximum stimulated reservoir volume. Hydraulic fracturing treatments are expensive and consume massive amounts of water, proppant, and chemicals. Thus, there is a need for developing improved fracturing treatments that do not require expensive components such as proppants.